Generally, a wind turbine includes a tower, a nacelle mounted on the tower, and a rotor coupled to the nacelle. The rotor typically includes a rotatable hub and a plurality of rotor blades coupled to and extending outwardly from the hub. Each rotor blade may be spaced about the hub so as to facilitate rotating the rotor to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy.
In many cases it is generally desirable to increase the size of wind turbines, and specifically the rotor blades thereof. Increasing the size of the rotor blades increases the amount of energy that can be captured by the rotor blades. Such size increases, however, would also increase the amount by which the rotor blades can deflect during operation. Increases in deflection may lead to the rotor blades striking the tower during operation, which can damage or destroy the wind turbine.
Accordingly, various attempts have been made to reduce the risk of rotor blades striking wind turbine towers during wind turbine operation. For example, rotor blade curvature has been modified to curve the rotor blades away from the tower. However, such modifications can reduce the amount of energy that can be captured by the rotor blades. Further, rotor blades have been angled away from the tower at angles known as cone angles. For example, the hub flange connecting a rotor blade to the hub or the rotor blade root may be angled at a cone angle. Alternatively, spacers have been attached between a rotor blade and a hub, with a first flange of the spacer connected directly to the hub and a second flange connected directly to the rotor blade, that provide a cone angle. These coning attempts, however, have a variety of drawbacks. For example, angling of the hub flange or rotor blade root may stress these components and cause ovalization concerns. Use of spacers directly connected to the hub and rotor blade may similarly stress the components and cause ovalization concerns, and further cause rotor blade wobbling during operation. Further, these various coning attempts may not adequately address the need to pitch the rotor blades during operation, by for example not adequately facilitating the inclusion and proper performance of bearing assemblies and bearing drive assemblies.
Accordingly, an improved wind turbine rotor that provides coning is desired in the art. For example, an insert that provides coning while addressing various long-felt needs as described above would be advantageous.